Electric furnace and method.



No. 871,273. PATENTED NOV. 19, 1907. P. L. T. HEROULT.

ELECTRIC FURNACE AND METHOD.

animaron HLED un a, 1907.

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WITNESSES:

f France, have invented certain new and use- 1 ,I TNITED STATES PATENT OFFIOE.

PAUL L. T. HROULT, Ol" LA PRAZ, FRANCE, ASSICNOR TO SOCIETE ELECTRO- METALLURGIQUE I `R.\N(,`AISIC, 0F FROGES. ISERE, FRANCE.

ELCTRIC FURNACE AND METlI-IOD.

Specification of Letters Patent.

Patented Nov. 19, 1907.

Application led May 3| 1907. Serial No, 371'692.

T o all whom tt may concern:

,Be it known that I, PAUL LOUIS TOUS- SAINT HROULT, a citizen of the Republic of France, residing at La -Praz, Savoie,

ful Im rovements in Electric Furnaces and Metho s, Of which the following is a specilication.

This invention aims to provide certain improvements whereby the operation of electric furnaces maybe simplified, and whereby especially the ldilficulties previously incident to' movable electrodes are eliminated. For thispurpose I prefer to introduce into the charge at a point between two fixed electrodes a device adapted to form part of the path of the current 4through the charge, and which I call a false or dummy" electrode. By varying the position of this false electrode, which is 4of conducting materialor at least of greater conductivity than the material of the charge, I vary the total resistance tothe passage of the current between the two electrodes, and so regulate the furnace. This false electrode may be more easily shifted than the true electrodes, since it does not require any electrical connections or 'sliding stuffingboxes or other objectionablev details. It may, for example, pass through the center of'a ring-shaped electrode arran ed a suitable distance above the base of t e furnace,

which base may be the other electrode. By lifting or lowering the false electrode the distance from the upper fixed electrode is not varied, butv that from the lower electrode or from the lmolten ortion of the charge is varied to produce t e desired vari ore and coke in the case o an ironsmeltingfurnace;

'Instead of the ring Cvarious other types of electrodes fixed at least during the opera- A`ring C of cartion of the furnace, may be utilized, such, for exam le, as those described in my application or patent, Serial No. 371,691, filed May 3, 1907, pending concurrently herewith.

The false electrode E may be a stick of carbon which is passed down through the center of the charge and is adjustable as by means of a screw F. It may be supported by aV metallic rod G which is made hollow in the manner shown for cooling by means of water or other Huid. For starting the furnace the false electrode E may be extended down to the hearth, or a packing of carbon may be interposed between the hearth and the lower end of the false electrode, and a similar packing of carbon may be introduced between the upper electrode C and the false electrode. After the furnace is set in operation the current passes approximately by way of the dotted ath shown. The electrode lC may be un ercut, and so arranged that the angle of the face of the charge immediately adjacent leaves a short gap, causing.

an are to spring from the electrode to the charge.

'Ihe top of the furnace may be left open as shown, and the regulation may be effected with the greatest ease by raising or lowering the false electrode E so as to increase or diminish the gap and consequently .the resistance between its lower end and the mass of molten material II in the bottom of the furnace.

The false or dummy electrode itself constitutes an invention which may be utilized with various types of furnaces other than that shown, such, for example, as multlphase furnaces.

Though I havedescribed with great particularity certain embodiments of my inven tion, yet it is not to be understood therefrom that the invention is restricted to the specific embodiments described. Various modifications thereof may be made by those skilled in the art without departure from the invention. i

What I claim is 1. An electric furnace having a pair of electrodes, a conductor adapted to form part of the path of the current between said electrodes, 'and means Ifor shifting said conductor to var the length of the part of the path forme thereby.

2. An electric furnace having a pair of fixed electrodes, and a false electrodel'adapted to form part of the path of the current through the charge, and adjustable to vary the length of such part.

3. An electric furnace having a base otv conducting material, a feeding shaft, a ring electrode at the base of said shaft, and a false electrode passing through said shaft and the charge to form part of the path of the current from the ring electrode to the hase, and ad- 10 justable to vary the length of said part.

4. Means for regulating the operation of an lentrm furnace consisting of a false or dummy electrode without electrical connections adapted to form part of the path of the current between the electrodes of the furnace, and to be shifted so as to vary the length of such part.

In `witness whereof, I have hereunto signed .my name in the presenceof two lsubscribing Witnesses. Y,

- PAUL L. T. HEROULT.

-Witnessesz DOMINGO A. USINA, THEODORE T. SNELL. 

